AndroidMARS学习笔记：Intent基础与应用

一、Intent概述

Intent是Android系统中用于组件间通信的重要机制。它不仅能够启动Activity、Service，还可以发送广播。通过Intent，开发者可以在不同的应用程序组件之间传递数据。

二、代码示例

1. activity_main.xml

    xmlns:tools="http://schemas.android.com/tools"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:paddingBottom="@dimen/activity_vertical_margin"
    android:paddingLeft="@dimen/activity_horizontal_margin"
    android:paddingRight="@dimen/activity_horizontal_margin"
    android:paddingTop="@dimen/activity_vertical_margin"
    tools:cOntext="com.example.intentexample.MainActivity">
            android:id="@+id/textView"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:text="@string/hello_world" />
            android:id="@+id/button"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:text="@string/btnText"/>

2. activity_other.xml

    xmlns:tools="http://schemas.android.com/tools"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:paddingBottom="@dimen/activity_vertical_margin"
    android:paddingLeft="@dimen/activity_horizontal_margin"
    android:paddingRight="@dimen/activity_horizontal_margin"
    android:paddingTop="@dimen/activity_vertical_margin"
    tools:cOntext="com.example.intentexample.OtherActivity">
            android:id="@+id/otherView"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:text="这是另一个Activity" />

3. MainActivity.java

package com.example.intentexample;
import android.app.Activity;
import android.content.Intent;
import android.net.Uri;
import android.os.Bundle;
import android.view.View;
import android.widget.Button;
public class MainActivity extends Activity {
    private Button mBtn = null;
    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        mBtn = findViewById(R.id.button);
        mBtn.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                Uri uri = Uri.parse("smsto://10086");
                Intent intent = new Intent(Intent.ACTION_SENDTO, uri);
                intent.putExtra("sms_body", "我当前的话费余额是多少？");
                startActivity(intent);
            }
        });
    }
}

4. OtherActivity.java

package com.example.intentexample;
import android.app.Activity;
import android.content.Intent;
import android.os.Bundle;
import android.widget.TextView;
public class OtherActivity extends Activity {
    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_other);
        Intent intent = getIntent();
        TextView otherView = findViewById(R.id.otherView);
        otherView.setText(intent.getStringExtra("extraKey"));
    }
}