我找到了一个办法来解决这个问题，但是这个办法可能不是很优雅，但是效果还不错。

其原理是将每一行的空格替换为固定宽度的ImageSpan(颜色为透明)。

public static void justify(final TextView textView) {

    final AtomicBoolean isJustify = new AtomicBoolean(false);

    final String textString = textView.getText().toString();

    final TextPaint textPaint = textView.getPaint();

    final SpannableStringBuilder builder = new SpannableStringBuilder();

    textView.post(new Runnable() {
        @Override
        public void run() {

            if (!isJustify.get()) {

                final int lineCount = textView.getLineCount();
                final int textViewWidth = textView.getWidth();

                for (int i = 0; i < lineCount; i++) {

                    int lineStart = textView.getLayout().getLineStart(i);
                    int lineEnd = textView.getLayout().getLineEnd(i);

                    String lineString = textString.substring(lineStart, lineEnd);

                    if (i == lineCount - 1) {
                        builder.append(new SpannableString(lineString));
                        break;
                    }

                    String trimSpaceText = lineString.trim();
                    String removeSpaceText = lineString.replaceAll(" ", "");

                    float removeSpaceWidth = textPaint.measureText(removeSpaceText);
                    float spaceCount = trimSpaceText.length() - removeSpaceText.length();

                    float eachSpaceWidth = (textViewWidth - removeSpaceWidth) / spaceCount;

                    SpannableString spannableString = new SpannableString(lineString);
                    for (int j = 0; j < trimSpaceText.length(); j++) {
                        char c = trimSpaceText.charAt(j);
                        if (c == ' ') {
                            Drawable drawable = new ColorDrawable(0x00ffffff);
                            drawable.setBounds(0, 0, (int) eachSpaceWidth, 0);
                            ImageSpan span = new ImageSpan(drawable);
                            spannableString.setSpan(span, j, j + 1, Spanned.SPAN_EXCLUSIVE_EXCLUSIVE);
                        }
                    }

                    builder.append(spannableString);
                }

                textView.setText(builder);
                isJustify.set(true);
            }
        }
    });
}

我把代码放在GitHub上: https://github.com/twiceyuan/TextJustification

概述:

Simplay我们可以使用android: justify mode ="inter_word"

 <TextView
 android:justificationMode="inter_word"
 android:id="@+id/messageTv"
 android:layout_width="match_parent"
 android:layout_height="wrap_content"
 android:layout_margin="@dimen/text_margin"
 android:paddingTop="15sp"
 android:textAppearance="@style/TextAppearance.Material3.TitleMedium" />

在github上可以看到

只需导入两个文件“textjustify yutils .java”和“TextViewEx.java”在你的项目。

public class TextJustifyUtils {
    // Please use run(...) instead
    public static void justify(TextView textView) {
        Paint paint = new Paint();

        String[] blocks;
        float spaceOffset = 0;
        float textWrapWidth = 0;

        int spacesToSpread;
        float wrappedEdgeSpace;
        String block;
        String[] lineAsWords;
        String wrappedLine;
        String smb = "";
        Object[] wrappedObj;

        // Pull widget properties
        paint.setColor(textView.getCurrentTextColor());
        paint.setTypeface(textView.getTypeface());
        paint.setTextSize(textView.getTextSize());

        textWrapWidth = textView.getWidth();
        spaceOffset = paint.measureText(" ");
        blocks = textView.getText().toString().split("((?<=\n)|(?=\n))");

        if (textWrapWidth < 20) {
            return;
        }

        for (int i = 0; i < blocks.length; i++) {
            block = blocks[i];

            if (block.length() == 0) {
                continue;
            } else if (block.equals("\n")) {
                smb += block;
                continue;
            }

            block = block.trim();

            if (block.length() == 0)
                continue;

            wrappedObj = TextJustifyUtils.createWrappedLine(block, paint,
                    spaceOffset, textWrapWidth);
            wrappedLine = ((String) wrappedObj[0]);
            wrappedEdgeSpace = (Float) wrappedObj[1];
            lineAsWords = wrappedLine.split(" ");
            spacesToSpread = (int) (wrappedEdgeSpace != Float.MIN_VALUE ? wrappedEdgeSpace
                    / spaceOffset
                    : 0);

            for (String word : lineAsWords) {
                smb += word + " ";

                if (--spacesToSpread > 0) {
                    smb += " ";
                }
            }

            smb = smb.trim();

            if (blocks[i].length() > 0) {
                blocks[i] = blocks[i].substring(wrappedLine.length());

                if (blocks[i].length() > 0) {
                    smb += "\n";
                }

                i--;
            }
        }

        textView.setGravity(Gravity.LEFT);
        textView.setText(smb);
    }

    protected static Object[] createWrappedLine(String block, Paint paint,
            float spaceOffset, float maxWidth) {
        float cacheWidth = maxWidth;
        float origMaxWidth = maxWidth;

        String line = "";

        for (String word : block.split("\\s")) {
            cacheWidth = paint.measureText(word);
            maxWidth -= cacheWidth;

            if (maxWidth <= 0) {
                return new Object[] { line, maxWidth + cacheWidth + spaceOffset };
            }

            line += word + " ";
            maxWidth -= spaceOffset;

        }

        if (paint.measureText(block) <= origMaxWidth) {
            return new Object[] { block, Float.MIN_VALUE };
        }

        return new Object[] { line, maxWidth };
    }

    final static String SYSTEM_NEWLINE = "\n";
    final static float COMPLEXITY = 5.12f; // Reducing this will increase
                                            // efficiency but will decrease
                                            // effectiveness
    final static Paint p = new Paint();

    public static void run(final TextView tv, float origWidth) {
        String s = tv.getText().toString();
        p.setTypeface(tv.getTypeface());
        String[] splits = s.split(SYSTEM_NEWLINE);
        float width = origWidth - 5;
        for (int x = 0; x < splits.length; x++)
            if (p.measureText(splits[x]) > width) {
                splits[x] = wrap(splits[x], width, p);
                String[] microSplits = splits[x].split(SYSTEM_NEWLINE);
                for (int y = 0; y < microSplits.length - 1; y++)
                    microSplits[y] = justify(removeLast(microSplits[y], " "),
                            width, p);
                StringBuilder smb_internal = new StringBuilder();
                for (int z = 0; z < microSplits.length; z++)
                    smb_internal.append(microSplits[z]
                            + ((z + 1 < microSplits.length) ? SYSTEM_NEWLINE
                                    : ""));
                splits[x] = smb_internal.toString();
            }
        final StringBuilder smb = new StringBuilder();
        for (String cleaned : splits)
            smb.append(cleaned + SYSTEM_NEWLINE);
        tv.setGravity(Gravity.LEFT);
        tv.setText(smb);
    }

    private static String wrap(String s, float width, Paint p) {
        String[] str = s.split("\\s"); // regex
        StringBuilder smb = new StringBuilder(); // save memory
        smb.append(SYSTEM_NEWLINE);
        for (int x = 0; x < str.length; x++) {
            float length = p.measureText(str[x]);
            String[] pieces = smb.toString().split(SYSTEM_NEWLINE);
            try {
                if (p.measureText(pieces[pieces.length - 1]) + length > width)
                    smb.append(SYSTEM_NEWLINE);
            } catch (Exception e) {
            }
            smb.append(str[x] + " ");
        }
        return smb.toString().replaceFirst(SYSTEM_NEWLINE, "");
    }

    private static String removeLast(String s, String g) {
        if (s.contains(g)) {
            int index = s.lastIndexOf(g);
            int indexEnd = index + g.length();
            if (index == 0)
                return s.substring(1);
            else if (index == s.length() - 1)
                return s.substring(0, index);
            else
                return s.substring(0, index) + s.substring(indexEnd);
        }
        return s;
    }

    private static String justifyOperation(String s, float width, Paint p) {
        float holder = (float) (COMPLEXITY * Math.random());
        while (s.contains(Float.toString(holder)))
            holder = (float) (COMPLEXITY * Math.random());
        String holder_string = Float.toString(holder);
        float lessThan = width;
        int timeOut = 100;
        int current = 0;
        while (p.measureText(s) < lessThan && current < timeOut) {
            s = s.replaceFirst(" ([^" + holder_string + "])", " "
                    + holder_string + "$1");
            lessThan = p.measureText(holder_string) + lessThan
                    - p.measureText(" ");
            current++;
        }
        String cleaned = s.replaceAll(holder_string, " ");
        return cleaned;
    }

    private static String justify(String s, float width, Paint p) {
        while (p.measureText(s) < width) {
            s = justifyOperation(s, width, p);
        }
        return s;
    }
}

and

public class TextViewEx extends TextView {
    private Paint paint = new Paint();

    private String[] blocks;
    private float spaceOffset = 0;
    private float horizontalOffset = 0;
    private float verticalOffset = 0;
    private float horizontalFontOffset = 0;
    private float dirtyRegionWidth = 0;
    private boolean wrapEnabled = false;
    int left, top, right, bottom = 0;
    private Align _align = Align.LEFT;
    private float strecthOffset;
    private float wrappedEdgeSpace;
    private String block;
    private String wrappedLine;
    private String[] lineAsWords;
    private Object[] wrappedObj;

    private Bitmap cache = null;
    private boolean cacheEnabled = false;

    public TextViewEx(Context context, AttributeSet attrs, int defStyle) {
        super(context, attrs, defStyle);
        // set a minimum of left and right padding so that the texts are not too
        // close to the side screen
        // this.setPadding(10, 0, 10, 0);
    }

    public TextViewEx(Context context, AttributeSet attrs) {
        super(context, attrs);
        // this.setPadding(10, 0, 10, 0);
    }

    public TextViewEx(Context context) {
        super(context);
        // this.setPadding(10, 0, 10, 0);
    }

    @Override
    public void setPadding(int left, int top, int right, int bottom) {
        // TODO Auto-generated method stub
        super.setPadding(left + 10, top, right + 10, bottom);
    }

    @Override
    public void setDrawingCacheEnabled(boolean cacheEnabled) {
        this.cacheEnabled = cacheEnabled;
    }

    public void setText(String st, boolean wrap) {
        wrapEnabled = wrap;
        super.setText(st);
    }

    public void setTextAlign(Align align) {
        _align = align;
    }

    @SuppressLint("NewApi")
    @Override
    protected void onDraw(Canvas canvas) {
        // If wrap is disabled then,
        // request original onDraw
        if (!wrapEnabled) {
            super.onDraw(canvas);
            return;
        }

        // Active canas needs to be set
        // based on cacheEnabled
        Canvas activeCanvas = null;

        // Set the active canvas based on
        // whether cache is enabled
        if (cacheEnabled) {

            if (cache != null) {
                // Draw to the OS provided canvas
                // if the cache is not empty
                canvas.drawBitmap(cache, 0, 0, paint);
                return;
            } else {
                // Create a bitmap and set the activeCanvas
                // to the one derived from the bitmap
                cache = Bitmap.createBitmap(getWidth(), getHeight(),
                        Config.ARGB_4444);
                activeCanvas = new Canvas(cache);
            }
        } else {
            // Active canvas is the OS
            // provided canvas
            activeCanvas = canvas;
        }

        // Pull widget properties
        paint.setColor(getCurrentTextColor());
        paint.setTypeface(getTypeface());
        paint.setTextSize(getTextSize());
        paint.setTextAlign(_align);
        paint.setFlags(Paint.ANTI_ALIAS_FLAG);

        // minus out the paddings pixel
        dirtyRegionWidth = getWidth() - getPaddingLeft() - getPaddingRight();
        int maxLines = Integer.MAX_VALUE;
        int currentapiVersion = android.os.Build.VERSION.SDK_INT;
        if (currentapiVersion >= android.os.Build.VERSION_CODES.JELLY_BEAN) {
            maxLines = getMaxLines();
        }
        int lines = 1;
        blocks = getText().toString().split("((?<=\n)|(?=\n))");
        verticalOffset = horizontalFontOffset = getLineHeight() - 0.5f; // Temp
                                                                        // fix
        spaceOffset = paint.measureText(" ");

        for (int i = 0; i < blocks.length && lines <= maxLines; i++) {
            block = blocks[i];
            horizontalOffset = 0;

            if (block.length() == 0) {
                continue;
            } else if (block.equals("\n")) {
                verticalOffset += horizontalFontOffset;
                continue;
            }

            block = block.trim();

            if (block.length() == 0) {
                continue;
            }

            wrappedObj = TextJustifyUtils.createWrappedLine(block, paint,
                    spaceOffset, dirtyRegionWidth);

            wrappedLine = ((String) wrappedObj[0]);
            wrappedEdgeSpace = (Float) wrappedObj[1];
            lineAsWords = wrappedLine.split(" ");
            strecthOffset = wrappedEdgeSpace != Float.MIN_VALUE ? wrappedEdgeSpace
                    / (lineAsWords.length - 1)
                    : 0;

            for (int j = 0; j < lineAsWords.length; j++) {
                String word = lineAsWords[j];
                if (lines == maxLines && j == lineAsWords.length - 1) {
                    activeCanvas.drawText("...", horizontalOffset,
                            verticalOffset, paint);

                } else if (j == 0) {
                    // if it is the first word of the line, text will be drawn
                    // starting from right edge of textview
                    if (_align == Align.RIGHT) {
                        activeCanvas.drawText(word, getWidth()
                                - (getPaddingRight()), verticalOffset, paint);
                        // add in the paddings to the horizontalOffset
                        horizontalOffset += getWidth() - (getPaddingRight());
                    } else {
                        activeCanvas.drawText(word, getPaddingLeft(),
                                verticalOffset, paint);
                        horizontalOffset += getPaddingLeft();
                    }

                } else {
                    activeCanvas.drawText(word, horizontalOffset,
                            verticalOffset, paint);
                }
                if (_align == Align.RIGHT)
                    horizontalOffset -= paint.measureText(word) + spaceOffset
                            + strecthOffset;
                else
                    horizontalOffset += paint.measureText(word) + spaceOffset
                            + strecthOffset;
            }

            lines++;

            if (blocks[i].length() > 0) {
                blocks[i] = blocks[i].substring(wrappedLine.length());
                verticalOffset += blocks[i].length() > 0 ? horizontalFontOffset
                        : 0;
                i--;
            }
        }

        if (cacheEnabled) {
            // Draw the cache onto the OS provided
            // canvas.
            canvas.drawBitmap(cache, 0, 0, paint);
        }
    }
}

现在，如果你使用普通的textView，比如:

<TextView
                android:id="@+id/original"
                android:layout_width="wrap_content"
                android:layout_height="wrap_content"
                android:text="@string/lorum_ipsum" />

简单地使用

<yourpackagename.TextViewEx
                android:id="@+id/changed"
                android:layout_width="wrap_content"
                android:layout_height="wrap_content"
                android:text="@string/lorum_ipsum" />

定义一个变量并将justify设为true，

TextViewEx changed = (TextViewEx) findViewById(R.id.changed);
changed.setText(getResources().getString(R.string.lorum_ipsum),true);

我不认为Android支持完全的理由。

更新2018-01-01:Android 8.0+支持TextView对齐模式。

非常简单的 我们可以在xml文件中这样做

<TextView 
android:justificationMode="inter_word"
/>

TextView在Android O提供了充分的理由(新的排版对齐)本身。 你只需要这样做:

科特林

if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.O) {
    textView.justificationMode = JUSTIFICATION_MODE_INTER_WORD
}

Java

if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.O) {
    textView.setJustificationMode(JUSTIFICATION_MODE_INTER_WORD);
}

XML

<TextView
    android:layout_width="wrap_content"
    android:layout_height="wrap_content"
    android:justificationMode="inter_word" />

默认值是jusication_mode_none (xml中的none)。