是的,我知道有AlertDialog。但我很惊讶地知道在Android中显示对话框有多么困难(好吧,至少不是程序员友好的)。
我曾经是一名。net开发人员,我想知道在android上是否有类似的功能?
if (MessageBox.Show("Sure?", "", MessageBoxButtons.YesNo) == DialogResult.Yes){
// Do something...
}
是的,我知道有AlertDialog。但我很惊讶地知道在Android中显示对话框有多么困难(好吧,至少不是程序员友好的)。
我曾经是一名。net开发人员,我想知道在android上是否有类似的功能?
if (MessageBox.Show("Sure?", "", MessageBoxButtons.YesNo) == DialogResult.Yes){
// Do something...
}
当前回答
显示对话框匿名作为命令链&没有定义另一个对象:
new AlertDialog.Builder(this).setTitle("Confirm Delete?")
.setMessage("Are you sure?")
.setPositiveButton("YES",
new DialogInterface.OnClickListener() {
public void onClick(DialogInterface dialog, int which) {
// Perform Action & Dismiss dialog
dialog.dismiss();
}
})
.setNegativeButton("NO", new DialogInterface.OnClickListener() {
@Override
public void onClick(DialogInterface dialog, int which) {
// Do nothing
dialog.dismiss();
}
})
.create()
.show();
其他回答
AlertDialog。Builder真的没有那么难用。一开始肯定有点吓人,但一旦你使用了一点,它就变得简单而强大了。我知道你说过你知道如何使用它,但这里只是一个简单的例子:
DialogInterface.OnClickListener dialogClickListener = new DialogInterface.OnClickListener() {
@Override
public void onClick(DialogInterface dialog, int which) {
switch (which){
case DialogInterface.BUTTON_POSITIVE:
//Yes button clicked
break;
case DialogInterface.BUTTON_NEGATIVE:
//No button clicked
break;
}
}
};
AlertDialog.Builder builder = new AlertDialog.Builder(context);
builder.setMessage("Are you sure?").setPositiveButton("Yes", dialogClickListener)
.setNegativeButton("No", dialogClickListener).show();
你也可以重用那个DialogInterface。OnClickListener如果你有其他是/否框,应该做同样的事情。
如果你是从视图中创建对话框。OnClickListener,你可以使用view.getContext()来获取Context。或者你也可以使用yourFragmentName.getActivity()。
你可以为决策实现一个通用的解决方案,并在另一种情况下使用,而不仅仅是yes/no和自定义警报动画或布局:
像这样的东西;首先创建用于传输数据的类:
public class AlertDecision {
private String question = "";
private String strNegative = "";
private String strPositive = "";
public AlertDecision question(@NonNull String question) {
this.question = question;
return this;
}
public AlertDecision ansPositive(@NonNull String strPositive) {
this.strPositive = strPositive;
return this;
}
public AlertDecision ansNegative(@NonNull String strNegative) {
this.strNegative = strNegative;
return this;
}
public String getQuestion() {
return question;
}
public String getAnswerNegative() {
return strNegative;
}
public String getAnswerPositive() {
return strPositive;
}
}
后的接口,用于返回结果
public interface OnAlertDecisionClickListener {
/**
* Interface definition for a callback to be invoked when a view is clicked.
*
* @param dialog the dialog that was clicked
* @param object The object in the position of the view
*/
void onPositiveDecisionClick(DialogInterface dialog, Object object);
void onNegativeDecisionClick(DialogInterface dialog, Object object);
}
现在你可以很容易地创建一个utils(在这个类中,你可以为警报实现不同的动画或自定义布局):
public class AlertViewUtils {
public static void showAlertDecision(Context context,
@NonNull AlertDecision decision,
final OnAlertDecisionClickListener listener,
final Object object) {
AlertDialog.Builder builder = new AlertDialog.Builder(context);
builder.setMessage(decision.getQuestion());
builder.setPositiveButton(decision.getAnswerPositive(),
new DialogInterface.OnClickListener() {
public void onClick(DialogInterface dialog, int which) {
listener.onPositiveDecisionClick(dialog, object);
}
});
builder.setNegativeButton(decision.getAnswerNegative(),
new DialogInterface.OnClickListener() {
public void onClick(DialogInterface dialog, int which) {
listener.onNegativeDecisionClick(dialog, object);
}
});
android.support.v7.app.AlertDialog dialog = builder.create();
dialog.show();
}
}
最后是活动或片段的召唤;你可以在你的案例或其他任务中使用这个:
public class MainActivity extends AppCompatActivity {
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity);
initResources();
}
public void initResources() {
Button doSomething = (Button) findViewById(R.id.btn);
doSomething.setOnClickListener(getDecisionListener());
}
private View.OnClickListener getDecisionListener() {
return new View.OnClickListener() {
@Override
public void onClick(View v) {
AlertDecision decision = new AlertDecision()
.question("question ...")
.ansNegative("negative action...")
.ansPositive("positive action... ");
AlertViewUtils.showAlertDecision(MainActivity.this,
decision, getOnDecisionListener(), v);
}
};
}
private OnAlertDecisionClickListener getOnDecisionListener() {
return new OnAlertDecisionClickListener() {
@Override
public void onPositiveDecisionClick(DialogInterface dialog, Object object) {
//do something like create, show views, etc...
}
@Override
public void onNegativeDecisionClick(DialogInterface dialog, Object object) {
//do something like delete, close session, etc ...
}
};
}
}
这里所有的答案都归结为冗长且不利于读者的代码:这正是提问者试图避免的。对我来说,最简单的方法是在这里使用lambdas:
new AlertDialog.Builder(this)
.setTitle("Are you sure?")
.setMessage("If you go back you will loose any changes.")
.setPositiveButton("Yes", (dialog, which) -> {
doSomething();
dialog.dismiss();
})
.setNegativeButton("No", (dialog, which) -> dialog.dismiss())
.show();
Android中的Lambdas需要retrolambda插件(https://github.com/evant/gradle-retrolambda),但无论如何,它对编写更清晰的代码非常有帮助。
Steve H的回答是正确的,但这里有更多的信息:对话框之所以以这种方式工作,是因为Android中的对话框是异步的(当对话框显示时,执行不会停止)。因此,您必须使用回调来处理用户的选择。
在关于Android和。net的区别(因为它涉及到对话框)的更长的讨论中,看看这个问题: 对话框/ alertdialog:如何在对话框启动时“阻止执行”(. net风格)
1.创建AlertDialog,设置消息、标题和正面、负面按钮:
final AlertDialog alertDialog = new AlertDialog.Builder(this)
.setCancelable(false)
.setTitle("Confirmation")
.setMessage("Do you want to remove this Picture?")
.setPositiveButton("Yes",null)
.setNegativeButton("No",null)
.create();
2.现在在DialogInterface上找到两个按钮,然后单击setOnClickListener():
alertDialog.setOnShowListener(new DialogInterface.OnShowListener() {
@Override
public void onShow(DialogInterface dialogInterface) {
Button yesButton = (alertDialog).getButton(android.app.AlertDialog.BUTTON_POSITIVE);
Button noButton = (alertDialog).getButton(android.app.AlertDialog.BUTTON_NEGATIVE);
yesButton.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View view) {
//Now Background Class To Update Operator State
alertDialog.dismiss();
Toast.makeText(GroundEditActivity.this, "Click on Yes", Toast.LENGTH_SHORT).show();
//Do Something here
}
});
noButton.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View view) {
alertDialog.dismiss();
Toast.makeText(GroundEditActivity.this, "Click on No", Toast.LENGTH_SHORT).show();
//Do Some Thing Here
}
});
}
});
3.To 显示警报对话框:
alertDialog.show();
注意:不要忘记AlertDialog的Final Keyword。