我想写一个模块，在点击一个按钮，相机打开，我可以点击和捕捉图像。如果我不喜欢图像，我可以删除它，然后点击另一个图像，然后选择图像，它应该返回并在活动中显示该图像。
当前回答
你可以使用此代码onClick监听器(你可以使用ImageView或按钮)
image.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View view) {
Intent takePictureIntent = new Intent(MediaStore.ACTION_IMAGE_CAPTURE);
if (takePictureIntent.resolveActivity(getPackageManager()) != null) {
startActivityForResult(takePictureIntent, 1);
}
}
});
在imageView中显示
@Override
protected void onActivityResult(int requestCode, int resultCode, Intent data) {
if (requestCode == REQUEST_IMAGE_CAPTURE && resultCode == RESULT_OK) {
Bundle extras = data.getExtras();
bitmap = (Bitmap) extras.get("data");
image.setImageBitmap(bitmap);
}
}
注意:将此插入舱单
<uses-feature android:name="android.hardware.camera" android:required="true" />
其他回答
更新(2020)
谷歌已经添加了一个新的ActivityResultRegistry API，“让你处理startActivityForResult() + onActivityResult()以及requestPermissions() + onRequestPermissionsResult()流，而无需覆盖你的活动或片段中的方法，通过ActivityResultContract带来了增加的类型安全性，并为测试这些流提供了钩子”。
该API是在androidx中添加的。和androidx.fragment 1.3.0-alpha02。
所以你现在可以这样做:
val takePicture = registerForActivityResult(ActivityResultContracts.TakePicture()) { success: Boolean ->
if (success) {
// The image was saved into the given Uri -> do something with it
}
}
val imageUri: Uri = ...
button.setOnClickListener {
takePicture.launch(imageUri)
}
查看文档了解如何使用新的Activity结果API: https://developer.android.com/training/basics/intents/result#kotlin
有许多内置的activityresultcontract，允许您做不同的事情，如选择联系人，请求权限，拍照或拍摄视频。您可能对ActivityResultContracts感兴趣。拍摄上图。
注意androidx.fragment 1.3.0-alpha04弃用了Fragment上的startActivityForResult() + onActivityResult()和requestPermissions() + onRequestPermissionsResult() api。因此，从现在开始ActivityResultContracts似乎是一种新的做事方式。
原答案(2015)
我花了好几个小时才把它修好。代码几乎是从developer.android.com复制粘贴而来的，只有细微的区别。
在AndroidManifest.xml上请求此权限:
<uses-permission android:name="android.permission.WRITE_EXTERNAL_STORAGE" />
在你的Activity中，首先定义这个:
static final int REQUEST_IMAGE_CAPTURE = 1;
private Bitmap mImageBitmap;
private String mCurrentPhotoPath;
private ImageView mImageView;
然后在onClick中触发这个Intent:
Intent cameraIntent = new Intent(MediaStore.ACTION_IMAGE_CAPTURE);
if (cameraIntent.resolveActivity(getPackageManager()) != null) {
// Create the File where the photo should go
File photoFile = null;
try {
photoFile = createImageFile();
} catch (IOException ex) {
// Error occurred while creating the File
Log.i(TAG, "IOException");
}
// Continue only if the File was successfully created
if (photoFile != null) {
cameraIntent.putExtra(MediaStore.EXTRA_OUTPUT, Uri.fromFile(photoFile));
startActivityForResult(cameraIntent, REQUEST_IMAGE_CAPTURE);
}
}
添加以下支持方法:
private File createImageFile() throws IOException {
// Create an image file name
String timeStamp = new SimpleDateFormat("yyyyMMdd_HHmmss").format(new Date());
String imageFileName = "JPEG_" + timeStamp + "_";
File storageDir = Environment.getExternalStoragePublicDirectory(
Environment.DIRECTORY_PICTURES);
File image = File.createTempFile(
imageFileName, // prefix
".jpg", // suffix
storageDir // directory
);
// Save a file: path for use with ACTION_VIEW intents
mCurrentPhotoPath = "file:" + image.getAbsolutePath();
return image;
}
然后接收结果:
@Override
protected void onActivityResult(int requestCode, int resultCode, Intent data) {
if (requestCode == REQUEST_IMAGE_CAPTURE && resultCode == RESULT_OK) {
try {
mImageBitmap = MediaStore.Images.Media.getBitmap(this.getContentResolver(), Uri.parse(mCurrentPhotoPath));
mImageView.setImageBitmap(mImageBitmap);
} catch (IOException e) {
e.printStackTrace();
}
}
}
使它工作的是MediaStore.Images.Media.getBitmap(this.getContentResolver()， Uri.parse(mCurrentPhotoPath))，这与developer.android.com的代码不同。原始代码给了我一个FileNotFoundException。
你得好好研究一下相机。(我认为要做到你想要的，你必须保存当前的图像到你的应用程序，在那里做选择/删除，然后召回相机再试一次，而不是直接在相机内部重试。)
下面是一个示例活动，它将启动相机应用程序，然后检索图像并显示它。
package edu.gvsu.cis.masl.camerademo;
import android.app.Activity;
import android.content.Intent;
import android.graphics.Bitmap;
import android.os.Bundle;
import android.view.View;
import android.widget.Button;
import android.widget.ImageView;
public class MyCameraActivity extends Activity
{
private static final int CAMERA_REQUEST = 1888;
private ImageView imageView;
private static final int MY_CAMERA_PERMISSION_CODE = 100;
@Override
public void onCreate(Bundle savedInstanceState)
{
super.onCreate(savedInstanceState);
setContentView(R.layout.main);
this.imageView = (ImageView)this.findViewById(R.id.imageView1);
Button photoButton = (Button) this.findViewById(R.id.button1);
photoButton.setOnClickListener(new View.OnClickListener()
{
@Override
public void onClick(View v)
{
if (checkSelfPermission(Manifest.permission.CAMERA) != PackageManager.PERMISSION_GRANTED)
{
requestPermissions(new String[]{Manifest.permission.CAMERA}, MY_CAMERA_PERMISSION_CODE);
}
else
{
Intent cameraIntent = new Intent(android.provider.MediaStore.ACTION_IMAGE_CAPTURE);
startActivityForResult(cameraIntent, CAMERA_REQUEST);
}
}
});
}
@Override
public void onRequestPermissionsResult(int requestCode, @NonNull String[] permissions, @NonNull int[] grantResults)
{
super.onRequestPermissionsResult(requestCode, permissions, grantResults);
if (requestCode == MY_CAMERA_PERMISSION_CODE)
{
if (grantResults[0] == PackageManager.PERMISSION_GRANTED)
{
Toast.makeText(this, "camera permission granted", Toast.LENGTH_LONG).show();
Intent cameraIntent = new Intent(android.provider.MediaStore.ACTION_IMAGE_CAPTURE);
startActivityForResult(cameraIntent, CAMERA_REQUEST);
}
else
{
Toast.makeText(this, "camera permission denied", Toast.LENGTH_LONG).show();
}
}
}
@Override
protected void onActivityResult(int requestCode, int resultCode, Intent data)
{
if (requestCode == CAMERA_REQUEST && resultCode == Activity.RESULT_OK)
{
Bitmap photo = (Bitmap) data.getExtras().get("data");
imageView.setImageBitmap(photo);
}
}
}
请注意，相机应用程序本身提供了查看/重拍图像的功能，一旦图像被接受，活动就会显示它。
下面是上面的活动使用的布局。它只是一个包含id为button1的Button和id为imageview1的ImageView的LinearLayout:
<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:orientation="vertical"
android:layout_width="fill_parent"
android:layout_height="fill_parent"
>
<Button android:id="@+id/button1" android:layout_width="wrap_content" android:layout_height="wrap_content" android:text="@string/photo"></Button>
<ImageView android:id="@+id/imageView1" android:layout_height="wrap_content" android:src="@drawable/icon" android:layout_width="wrap_content"></ImageView>
</LinearLayout>
最后一个细节，一定要加上:
<uses-feature android:name="android.hardware.camera"></uses-feature>
如果摄像头是你应用功能的可选选项。请确保在权限中将require设置为false。像这样
<uses-feature android:name="android.hardware.camera" android:required="false"></uses-feature>
到你的manifest.xml。
在活动:
@Override
protected void onCreate(Bundle savedInstanceState) {
image = (ImageView) findViewById(R.id.imageButton);
image.setOnClickListener(new OnClickListener() {
@Override
public void onClick(View v) {
try {
SimpleDateFormat sdfPic = new SimpleDateFormat(DATE_FORMAT);
currentDateandTime = sdfPic.format(new Date()).replace(" ", "");
File imagesFolder = new File(IMAGE_PATH, currentDateandTime);
imagesFolder.mkdirs();
Random generator = new Random();
int n = 10000;
n = generator.nextInt(n);
String fname = IMAGE_NAME + n + IMAGE_FORMAT;
File file = new File(imagesFolder, fname);
outputFileUri = Uri.fromFile(file);
cameraIntent= new Intent(
android.provider.MediaStore.ACTION_IMAGE_CAPTURE);
cameraIntent.putExtra(MediaStore.EXTRA_OUTPUT, outputFileUri);
startActivityForResult(cameraIntent, CAMERA_DATA);
}catch(Exception e) {
e.printStackTrace();
}
}
});
@Override
public void onActivityResult(int requestCode, int resultCode, Intent data) {
super.onActivityResult(requestCode, resultCode, data);
switch(requestCode) {
case CAMERA_DATA :
final int IMAGE_MAX_SIZE = 300;
try {
// Bitmap bitmap;
File file = null;
FileInputStream fis;
BitmapFactory.Options opts;
int resizeScale;
Bitmap bmp;
file = new File(outputFileUri.getPath());
// This bit determines only the width/height of the
// bitmap
// without loading the contents
opts = new BitmapFactory.Options();
opts.inJustDecodeBounds = true;
fis = new FileInputStream(file);
BitmapFactory.decodeStream(fis, null, opts);
fis.close();
// Find the correct scale value. It should be a power of
// 2
resizeScale = 1;
if (opts.outHeight > IMAGE_MAX_SIZE
|| opts.outWidth > IMAGE_MAX_SIZE) {
resizeScale = (int) Math.pow(2, (int) Math.round(Math.log(IMAGE_MAX_SIZE/ (double) Math.max(opts.outHeight, opts.outWidth)) / Math.log(0.5)));
}
// Load pre-scaled bitmap
opts = new BitmapFactory.Options();
opts.inSampleSize = resizeScale;
fis = new FileInputStream(file);
bmp = BitmapFactory.decodeStream(fis, null, opts);
Bitmap getBitmapSize = BitmapFactory.decodeResource(
getResources(), R.drawable.male);
image.setLayoutParams(new RelativeLayout.LayoutParams(
200,200));//(width,height);
image.setImageBitmap(bmp);
image.setRotation(90);
fis.close();
ByteArrayOutputStream baos = new ByteArrayOutputStream();
bmp.compress(Bitmap.CompressFormat.JPEG, 70, baos);
imageByte = baos.toByteArray();
break;
} catch (FileNotFoundException e) {
e.printStackTrace();
} catch (IOException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
}
}
在layout.xml:
enter code here
<RelativeLayout
android:id="@+id/relativeLayout2"
android:layout_width="wrap_content"
android:layout_height="wrap_content">
<ImageView
android:id="@+id/imageButton"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:src="@drawable/XXXXXXX"
android:textAppearance="?android:attr/textAppearanceSmall" />
在manifest.xml:
< uses-permission android: name = " android.permission。CAMERA" /> <uses-feature android:name="android.硬件。相机" / >
我知道这是一个相当老的线程，但所有这些解决方案都没有完成，当用户旋转相机时，不工作在一些设备上，因为onActivityResult中的数据是空的。这是我在很多设备上测试过的解决方案，到目前为止还没有遇到任何问题。
首先在activity中声明Uri变量:
private Uri uriFilePath;
然后创建临时文件夹，用于存储捕获的图像，并通过相机捕获图像:
PackageManager packageManager = getActivity().getPackageManager();
if (packageManager.hasSystemFeature(PackageManager.FEATURE_CAMERA)) {
File mainDirectory = new File(Environment.getExternalStorageDirectory(), "MyFolder/tmp");
if (!mainDirectory.exists())
mainDirectory.mkdirs();
Calendar calendar = Calendar.getInstance();
uriFilePath = Uri.fromFile(new File(mainDirectory, "IMG_" + calendar.getTimeInMillis()));
intent = new Intent(MediaStore.ACTION_IMAGE_CAPTURE);
intent.putExtra(MediaStore.EXTRA_OUTPUT, uriFilePath);
startActivityForResult(intent, 1);
}
这里有一个最重要的事情，你必须保存你的uriFilePath在onSaveInstanceState中，因为如果你不这样做，用户在使用camera时旋转他的设备，你的uri将为null。
@Override
protected void onSaveInstanceState(Bundle outState) {
if (uriFilePath != null)
outState.putString("uri_file_path", uriFilePath.toString());
super.onSaveInstanceState(outState);
}
之后，你应该在onCreate方法中恢复你的uri:
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
if (savedInstanceState != null) {
if (uriFilePath == null && savedInstanceState.getString("uri_file_path") != null) {
uriFilePath = Uri.parse(savedInstanceState.getString("uri_file_path"));
}
}
}
这里是最后一部分，获得你的Uri在onActivityResult:
@Override
protected void onActivityResult(int requestCode, int resultCode, Intent data) {
if (resultCode == RESULT_OK) {
if (requestCode == 1) {
String filePath = uriFilePath.getPath(); // Here is path of your captured image, so you can create bitmap from it, etc.
}
}
}
附注:别忘了在你的Manifest中添加Camera和Ext. storage的写入权限。
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