Activity间中使用Intent传值

时间：2021-05-15 18:43:36

主页面用来输入一个值传入第二个页面显示，关闭第二个页面返回一个值

主页布局：

<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"

    xmlns:tools="http://schemas.android.com/tools"

    android:layout_width="match_parent"

    android:layout_height="match_parent"

    tools:context=".MainActivity" >

    <TextView

        android:id="@+id/view"

        android:layout_width="match_parent"

        android:layout_height="wrap_content"

        android:text="关闭第二个页面后返回值" />

    <EditText

        android:id="@+id/txt"

        android:layout_width="match_parent"

        android:layout_height="wrap_content"

        android:layout_below="@id/view"

        android:text="" />

    <Button

        android:id="@+id/btn"

        android:layout_width="match_parent"

        android:layout_height="wrap_content"

        android:layout_below="@id/txt"

        android:text="转第二页" />

</RelativeLayout>

MainActivity，主要通过startActivityForResult来传递请求码，返回数据的时候，第二个页面调用Activity.setResult()方法设置返回Intent以及返回码，需要重写源Activity的onActivityResult()方法以便于接受返回的Intent，在onActivityResult()中会判断请求码和响应码

package com.example.android01;

import android.os.Bundle;

import android.R.string;

import android.app.Activity;

import android.content.Intent;

import android.util.Log;

import android.view.Menu;

import android.view.View;

import android.view.View.OnClickListener;

import android.widget.Button;

import android.widget.EditText;

import android.widget.Toast;

public class MainActivity extends Activity {

    private final static String TAG="MainActivity";

    private final static int REQUEST_CODE = 1;

    private final static String CONTENT = "content";

    private EditText txtEditText = null;

    private Button btnButton = null;

    @Override

    protected void onCreate(Bundle savedInstanceState) {

        super.onCreate(savedInstanceState);

        setContentView(R.layout.activity_main);

        txtEditText = (EditText) this.findViewById(R.id.txt);

        if (savedInstanceState != null && savedInstanceState.containsKey(CONTENT)) {

            txtEditText.setText(savedInstanceState.getString(CONTENT) + "[2]");

        }

        btnButton = (Button) this.findViewById(R.id.btn);

        btnButton.setOnClickListener(new OnClickListener() {

            @Override

            public void onClick(View v) {

                Intent intent = new Intent(MainActivity.this, SecondActivity.class);

                String str=txtEditText.getText().toString();

                intent.putExtra("fromMain", str);

                // startActivity(intent);

                // 启动需要监听返回值的Activity，并设置请求码：requestCode

                startActivityForResult(intent, REQUEST_CODE);

            }

        });

    }

    /*

     * (non-Javadoc)

     *

     * @see android.app.Activity#onActivityResult(int, int,

     * android.content.Intent)

     */

    @Override

    protected void onActivityResult(int requestCode, int resultCode, Intent data) {

        // 当otherActivity中返回数据的时候，会响应此方法

        // requestCode和resultCode必须与请求startActivityForResult()和返回setResult()的时候传入的值一致。

        if (requestCode == REQUEST_CODE && resultCode == SecondActivity.RESULT_CODE) {

            Bundle bundle=data.getExtras();

            String strResult = bundle.getString("result");

            Log.i(TAG,"onActivityResult: "+ strResult);

            Toast.makeText(MainActivity.this, strResult, Toast.LENGTH_LONG).show();

        }

    }

    /*

     * (non-Javadoc) 保存Activity页面状态在onStop之前执行

     */

    @Override

    protected void onSaveInstanceState(Bundle outState) {

        // TODO Auto-generated method stub

        super.onSaveInstanceState(outState);

        String contentString = txtEditText.getText().toString();

        outState.putString(CONTENT, contentString);

    }

    /*

     * (non-Javadoc)

     *

     * @see android.app.Activity#onCreateOptionsMenu(android.view.Menu)

     */

    @Override

    public boolean onCreateOptionsMenu(Menu menu) {

        // Inflate the menu; this adds items to the action bar if it is present.

        getMenuInflater().inflate(R.menu.activity_main, menu);

        return true;

    }

}

每二个Activity

/**

 *

 */

package com.example.android01;

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;

import android.widget.EditText;

import android.widget.TextView;

/**

 * @author Administrator 2014-3-12 下午10:21:17

 */

public class SecondActivity extends Activity {

    private final static String TAG="MainActivity";

    public final static int RESULT_CODE=1;

    private Button btnBack = null;

    private EditText txtContent = null;

    private TextView viewContent = null;

    /*

     * (non-Javadoc)

     *

     * @see android.app.Activity#onCreate(android.os.Bundle)

     */

    @Override

    protected void onCreate(Bundle savedInstanceState) {

        // TODO Auto-generated method stub

        super.onCreate(savedInstanceState);

        setContentView(R.layout.secondactivity);

        txtContent = (EditText) this.findViewById(R.id.txtContent);

        viewContent = (TextView) this.findViewById(R.id.viewContent);

        btnBack = (Button) this.findViewById(R.id.btnBack);

        Intent intent = getIntent();

        Bundle bundle = intent.getExtras();

        String strContentString = bundle.getString("fromMain");

        Log.i(TAG,"SecondActivity: "+ strContentString);

        viewContent.setText(strContentString);

        btnBack.setOnClickListener(new OnClickListener() {

            @Override

            public void onClick(View arg0) {

                Intent intent = new Intent();

                intent.putExtra("result", txtContent.getText().toString());

                setResult(RESULT_CODE, intent);// 设置resultCode，onActivityResult()中能获取到

                finish();

            }

        });

    }

}

注意请求码与返回码的对应判断，因为可能有多个请求码与返回码。

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