package com.yanzitong.activitytest6117; import android.content.Intent; import android.os.Bundle; import android.widget.Button; import androidx.appcompat.app.AppCompatActivity; public class ThirdActivity extends AppCompatActivity { private Button mThirdBtn1; private Button mThirdBtn2; private Button mThirdBtn3; @Override protected void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); setContentView(R.layout.third_layout); mThirdBtn1 = findViewById(R.id.third_btn1); mThirdBtn1.setOnClickListener(v -> { // 项目内部隐式Intent:匹配action和category Intent intent = new Intent("com.yanzitong.activitytest6117.action.YZT_FIRST"); // 为FirstActivity定义对应的action intent.addCategory("com.yanzitong.activitytest6117.category.YZT_FIRST"); startActivity(intent); }); mThirdBtn2 = findViewById(R.id.third_btn2); mThirdBtn3 = findViewById(R.id.third_btn3); mThirdBtn2.setOnClickListener(v -> { Intent intent = new Intent(Intent.ACTION_VIEW); // 等价于"Intent intent = new Intent(android.intent.action.VIEW)" startActivity(intent); }); mThirdBtn3.setOnClickListener(v -> { Intent intent = new Intent(); startActivity(intent); }); } // 隐式Intent——项目内部或项目之间的调用 // 1. 实现ThirdActivity返回FirstActivity /** * 为FirstActivity定义对应的action和category的值 * category可以是默认值,不可缺 * category自定义 */ }