onBackPressed() 使用 .

2012-10-26 17:16
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onBackPressed() : 当手机按下back键时，执行此方法。

用此方法时 ：有super.onBackPressed() 时 不能把在此方法中设置的 intent 传回上一个Activity ，

因此 去掉super.onBackPressed() 在末尾加上finish（）；

在上一个activity中用onActivityResult() 方法接受上此Activity的onBackPressed()方法传回去的intent，

在onBackPressed（）设置resultCode 在上一个Activity 的OnActivityResult（）中验证；

接受Activity：

[html]
view plaincopyprint?

package com.orient; import android.app.Activity; import android.content.Intent; import android.os.Bundle; import android.view.View; import android.view.View.OnClickListener; import android.widget.Button; import android.widget.TextView; public class TestProjectActivity extends Activity { String result; TextView view; @Override public void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); setContentView(R.layout.main); view = (TextView) findViewById(R.id.text); Button back = (Button) findViewById(R.id.button); back.setOnClickListener(new OnClickListener() { @Override public void onClick(View v) { Intent intent = new Intent(TestProjectActivity.this, CopyOfTestProjectActivity.class); startActivityForResult(intent, 1111); } }); } @Override protected void onActivityResult(int requestCode, int resultCode, Intent data) { super.onActivityResult(requestCode, resultCode, data); if (requestCode == 1111 && resultCode == 111 && data != null) { result = data.getStringExtra("activity2"); view.setText(result); } } }

package com.orient;

import android.app.Activity;
import android.content.Intent;
import android.os.Bundle;
import android.view.View;
import android.view.View.OnClickListener;
import android.widget.Button;
import android.widget.TextView;

public class TestProjectActivity extends Activity {
String result;
TextView view;

@Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.main);

view = (TextView) findViewById(R.id.text);

Button back = (Button) findViewById(R.id.button);
back.setOnClickListener(new OnClickListener() {

@Override
public void onClick(View v) {

Intent intent = new Intent(TestProjectActivity.this,
CopyOfTestProjectActivity.class);
startActivityForResult(intent, 1111);
}
});
}

@Override
protected void onActivityResult(int requestCode, int resultCode, Intent data) {
super.onActivityResult(requestCode, resultCode, data);
if (requestCode == 1111 && resultCode == 111 && data != null) {
result = data.getStringExtra("activity2");
view.setText(result);
}
}
}

传值Activity：

[html]
view plaincopyprint?

package com.orient;

import android.app.Activity;
import android.content.Intent;
import android.os.Bundle;
import android.util.Log;
import android.view.View;
import android.view.View.OnClickListener;
import android.widget.Button;

public class CopyOfTestProjectActivity extends Activity {
@Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.main2);

Log.v("Test21", "Display onBackPressed");
}

@Override
public void onBackPressed() {
Intent intent=new Intent();
intent.putExtra("activity2", "TestText");
setResult(111, intent);
finish();
}

}