Intent使用详解

标签（空格分隔）： intent menu

Intent的使用方式

• 显示启动
• 隐式启动

显示Intent

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

隐式Intent

1.跳转到Activity

在清单文件中加入action，category

<activity android:name=".SecondActivity">            <intent-filter>                <action android:name="com.example.seele.activitytest.ACTION_START" />                <category android:name="android.intent.category.DEFAULT"/>                <category android:name="com.example.seele.activitytest.MY_CATEGORY" />            </intent-filter></activity>

android.intent.category.DEFAULT 是默认的category

Intent intent = new Intent("com.example.seele.activitytest.ACTION_START");        intent.addCategory("com.example.seele.activitytest.MY_CATEGORY");        startActivity(intent);

2.跳转到网页

Intent intent = new Intent(Intent.ACTION_VIEW);                intent.setData(Uri.parse("http://www.baidu.com"));                startActivity(intent);

如果在清单文件中Activity加入action，catrgory，程序会让我们选择可以打开的界面（浏览器，ThirdActivity）

<activity android:name=".ThirdActivity">            <intent-filter>                <action android:name="android.intent.action.VIEW"/>                <category android:name="android.intent.category.DEFAULT"/>                <data android:scheme="http"/>            </intent-filter>        </activity>

3.跳转到拨号

Intent intent = new Intent(Intent.ACTION_DIAL);                intent.setData(Uri.parse("tel:10086"));                startActivity(intent);

4.Intent传递数据

//传递的activityString data  = "Hello SecondActivity";                Intent intent = new Intent(FirstActivity.this,SecondActivity.class);                intent.putExtra("extra_data",data);                startActivity(intent);

//接收的activity Intent intent = getIntent();        String data = getIntent().getStringExtra("extra_data");

5.返回给上一个活动数据

startActivityForResult传递的两个参数是 intent 和 请求码
onActivityResult传递的三个参数是requestCode（请求码） resultCode（处理结果） data（返回的数据）

FirstActivitybtn7.setOnClickListener(new View.OnClickListener() {            @Override            public void onClick(View v) {                Intent intent = new Intent(FirstActivity.this,SecondActivity.class);                startActivityForResult(intent,1);            }        }); @Override    protected void onActivityResult(int requestCode, int resultCode, Intent data) {        switch (requestCode){            case 1:                if(resultCode==RESULT_OK){                    String returnedData = data.getStringExtra("data_return");                    Toast.makeText(this,returnedData,Toast.LENGTH_SHORT).show();                }                break;        }        super.onActivityResult(requestCode, resultCode, data);    }

SecondActivity@Override    public void onBackPressed() {        Intent intent = new Intent();        intent.putExtra("data_return","Hello FirstActivity");        setResult(RESULT_OK,intent);        finish();    }

---

在res目录新建一个menu文件夹，menu文件夹中新建main

<?xml version="1.0" encoding="utf-8"?><menu xmlns:android="http://schemas.android.com/apk/res/android">    <item        android:id="@+id/add_item"        android:title="Add"/>    <item        android:id="@+id/remove_item"        android:title="Remove"/></menu>

在Activity中重写onCreateOptionsMenu和onOptionsItemSelected

public class FirstActivity extends AppCompatActivity {    @Override    protected void onCreate(Bundle savedInstanceState) {        super.onCreate(savedInstanceState);        setContentView(R.layout.first_layout);    }    @Override    public boolean onCreateOptionsMenu(Menu menu) {        getMenuInflater().inflate(R.menu.main,menu);        return true;    }    @Override    public boolean onOptionsItemSelected(MenuItem item) {        switch (item.getItemId()){            case R.id.add_item:                Toast.makeText(this,"You clicked Add",Toast.LENGTH_SHORT).show();                break;            case  R.id.remove_item:                Toast.makeText(this,"You clicked Remove",Toast.LENGTH_SHORT).show();                break;        }        return true;    }}

源码下载