Android组件Activity

Intent和IntentFilter

package com.example.intentdemo;

import android.content.Intent;
import android.support.v7.app.AppCompatActivity;
import android.os.Bundle;
import android.view.View;

public class MainActivity extends AppCompatActivity {

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
    }

    public void btn_startSecond_onclick(View view) {
        Intent intent = new Intent(MainActivity.this, SecondActivity.class);
        startActivity(intent);        //调用Activity给提供的startActivity方法将intent传入
    }
}

      data属性赋值为http或https，也就是说当我们传递了具有http开头或者https开头的网址的时候，也就是符合了过滤器所需要过滤出来的数据的特征的时候，就能够筛选出我们自定义的浏览器作为启动的一个备选的应用

      原理可以看做是白名单的筛选的模式，凡是我们要打开的应用符合我们所制定的属性的值的时候，都可以筛选出来作为我们的备选项

Activity的传值

 

Activity的生命周期

package com.example.activity_lifecycle;

import android.support.v7.app.AppCompatActivity;
import android.os.Bundle;
import android.util.Log;

import javax.security.auth.login.LoginException;

public class MainActivity extends AppCompatActivity {
    private static final String TAG = "MainActivity";

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        Log.e(TAG, "onCreate: is running");
    }

    @Override
    protected void onStart() {
        super.onStart();
        Log.e(TAG, "onStart: is running");
    }


    @Override
    protected void onResume() {
        super.onResume();
        Log.e(TAG, "onResume: is running");
    }

    @Override
    protected void onPause() {
        super.onPause();
        Log.e(TAG, "onPause: is running");
    }

    @Override
    protected void onStop() {
        super.onStop();
        Log.e(TAG, "onStop: is running");
    }

    @Override
    protected void onDestroy() {
        super.onDestroy();
        Log.e(TAG, "onDestroy: is running");
    }

}

Activity的启动模式

可以多次启动同一个Activity

package com.example.launchmodedemo;

import android.content.Intent;
import android.support.v7.app.AppCompatActivity;
import android.os.Bundle;
import android.util.Log;
import android.view.View;

public class MainActivity extends AppCompatActivity {
    private static final String TAG = "MainActivity";

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        Log.e(TAG, "onCreate: "+this.toString() );
    }

    public void btn_start(View view) {
        Intent intent = new Intent(this, MainActivity.class);
        startActivity(intent);
    }
}

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