[Android] 开发第十一天

Posted 2020-10-02 秤心

MainActivity.java 代码如下：

package com.oazzz.test9;

import android.support.annotation.Nullable;
import android.support.v7.app.AppCompatActivity;
import android.os.Bundle;
import android.view.View;
import android.widget.EditText;
import android.widget.TextView;
import android.widget.Toast;

public class MainActivity extends AppCompatActivity implements View.OnClickListener {
    // 事件监听器的几种实现方式
    // 1. 内部类形式
    // 2. 外部类形式
    // 3. Activity 本身作为事件监听器类
    // 4. 匿名内部类形式
    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);

        TextView c1 = (TextView) findViewById(R.id.c1);
        c1.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View view) {
                Toast.makeText(view.getContext(), "点击了第一行文本！", Toast.LENGTH_LONG).show();
            }
        });

        TextView c2 = (TextView) findViewById(R.id.c2);
        c2.setOnClickListener(new ButtonClickListener());

        TextView c3 = (TextView) findViewById(R.id.c3);
        c3.setOnClickListener(this);
    }

    @Override
    public void onClick(View view) {
        Toast.makeText(view.getContext(), "点击了第三行文本！", Toast.LENGTH_LONG).show();
    }

    public void clickHandler(View view){
        Toast.makeText(view.getContext(), "点击了第四行文本！", Toast.LENGTH_SHORT).show();
    }

    private final class ButtonClickListener implements View.OnClickListener{
        @Override
        public void onClick(View view) {
            Toast.makeText(view.getContext(), "点击了第二行文本！", Toast.LENGTH_SHORT).show();
        }
    }
}

activity_main.xml 代码如下：

<?xml version="1.0" encoding="utf-8"?>
<android.support.constraint.ConstraintLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:app="http://schemas.android.com/apk/res-auto"
    xmlns:tools="http://schemas.android.com/tools"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    tools:context="com.oazzz.test9.MainActivity">

    <TextView
        android:id="@+id/c1"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:text="@string/c1"
        app:layout_constraintBottom_toBottomOf="parent"
        app:layout_constraintLeft_toLeftOf="parent"
        app:layout_constraintRight_toRightOf="parent"
        app:layout_constraintTop_toTopOf="parent"
        app:layout_constraintVertical_bias="0.2" />


    <TextView
        android:id="@+id/c2"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:text="@string/c2"
        app:layout_constraintBottom_toBottomOf="parent"
        app:layout_constraintLeft_toLeftOf="parent"
        app:layout_constraintRight_toRightOf="parent"
        app:layout_constraintTop_toTopOf="parent"
        app:layout_constraintVertical_bias="0.4" />


    <TextView
        android:id="@+id/c3"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:text="@string/c3"
        app:layout_constraintBottom_toBottomOf="parent"
        app:layout_constraintLeft_toLeftOf="parent"
        app:layout_constraintRight_toRightOf="parent"
        app:layout_constraintTop_toTopOf="parent"
        app:layout_constraintVertical_bias="0.6" />


    <TextView
        android:id="@+id/c4"
        android:onClick="clickHandler"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:text="@string/c4"
        app:layout_constraintBottom_toBottomOf="parent"
        app:layout_constraintLeft_toLeftOf="parent"
        app:layout_constraintRight_toRightOf="parent"
        app:layout_constraintTop_toTopOf="parent"
        app:layout_constraintVertical_bias="0.8" />

</android.support.constraint.ConstraintLayout>

Android-Studio 中 自动生成重载代码的菜单项在 Generate -> Override Methods...