AS基本使用

Android开发入门

build.gradle

plugins {
    id 'com.android.application'
}

android {
    compileSdkVersion 35
    buildToolsVersion "35.0.0"

    defaultConfig {
        applicationId "com.example.demo"
        minSdkVersion 16
        targetSdkVersion 35
        versionCode 1
        versionName "1.0"

        testInstrumentationRunner "androidx.test.runner.AndroidJUnitRunner"
        externalNativeBuild {
            cmake {
                cppFlags '-std=c++11'
            }
        }
    }

    buildTypes {
        release {
            minifyEnabled false
            proguardFiles getDefaultProguardFile('proguard-android-optimize.txt'), 'proguard-rules.pro'
        }
    }
    compileOptions {
        sourceCompatibility JavaVersion.VERSION_1_8
        targetCompatibility JavaVersion.VERSION_1_8
    }
    externalNativeBuild {
        cmake {
            path file('src/main/cpp/CMakeLists.txt')
            version '3.10.2'
        }
    }
    buildFeatures {
        viewBinding true
    }
}

dependencies {
    
    implementation 'androidx.appcompat:appcompat:1.2.0'
    implementation 'com.google.android.material:material:1.2.1'
    implementation 'androidx.constraintlayout:constraintlayout:2.0.1'
    testImplementation 'junit:junit:4.+'
    androidTestImplementation 'androidx.test.ext:junit:1.1.2'
    androidTestImplementation 'androidx.test.espresso:espresso-core:3.3.0'
}

AndroidManifest.xml

<?xml version="1.0" encoding="utf-8"?>
<manifest xmlns:android="http://schemas.android.com/apk/res/android"
    package="com.example.demo">

    <application
        android:allowBackup="true"
        android:icon="@mipmap/ic_launcher"
        android:label="@string/app_name"
        android:roundIcon="@mipmap/ic_launcher_round"
        android:supportsRtl="true"
        android:theme="@style/Theme.Demo">
        <activity android:name=".MainActivity">
            <intent-filter>
                <action android:name="android.intent.action.MAIN" />

                <category android:name="android.intent.category.LAUNCHER" />
            </intent-filter>
        </activity>
    </application>

</manifest>

安卓程序执行路口

如果app带有application的话，执行入口就在application中的android:name所指向的类中，一般的app里面都没有application，加固的app中一般都有application

application指向的类程序员能控制的最早的类

基本控件的使用

Button

使用android:onClick 进行绑定点击事件

<Button
    android:id="@+id/button"
    android:layout_width="283dp"
    android:layout_height="71dp"
    android:text="Button"
    app:layout_constraintBottom_toBottomOf="parent"
    app:layout_constraintEnd_toEndOf="parent"
    app:layout_constraintStart_toStartOf="parent"
    app:layout_constraintTop_toTopOf="parent"
    app:layout_constraintVertical_bias="0.345"
    android:onClick="test"
    />

public void test(View view) {
    Log.d("xiaojianbang","test test");
}

使用id进行绑定

    <Button
        android:id="@+id/button"
        android:layout_width="283dp"
        android:layout_height="71dp"
        android:text="Button"
        app:layout_constraintBottom_toBottomOf="parent"
        app:layout_constraintEnd_toEndOf="parent"
        app:layout_constraintStart_toStartOf="parent"
        app:layout_constraintTop_toTopOf="parent"
        app:layout_constraintVertical_bias="0.345"
        />
Button button = binding.button;
button.setOnClickListener(new View.onCLickListener(
	@Override
	public void onCick(View view){
		Lod.d("xiaojianbang","onClick");
	}
));

使用多态的方式进行绑定

    <Button
        android:id="@+id/button"
        android:layout_width="283dp"
        android:layout_height="71dp"
        android:text="Button"
        app:layout_constraintBottom_toBottomOf="parent"
        app:layout_constraintEnd_toEndOf="parent"
        app:layout_constraintStart_toStartOf="parent"
        app:layout_constraintTop_toTopOf="parent"
        app:layout_constraintVertical_bias="0.345"
        />

Button button = binding.button;
button.newOnClickListener(new MyClick());

class MyClick implements View.OnClickListener{
	@Override
	public void onClick(View view){
		Log.d("xiaojianbang",onClickMyClick);
	}
}

直接让MainActivity实现接口

有多种按钮时采用这个方法

public class MainActivity extends AppCompatActivity implements 

button.setOnClickListerner(this);

有多个按钮时，采用view.getId()进行区分

sdk/tools/bin/uiautomatorviewer.bat可以看到控件id

Toast

@Overrid
public void onClick(View view){
    switch(view.getId()){
        case R.id.button:
            Log.d("xiaojianbang","onClick");
            Toast.makeText(Main.this,"xiaojianbang",Toast.LENGTH_LONG).show();
    }
}

TextView

TextView textView = binding.textVeiw;
@Override vodi onClick(View view){
    switch(view.getId()){
        case R.id.button:
            Log.d("xiaojianbang",MainOnClick);
            Toast.makeText(MainActivity.this,"xiaojianbang",Toast.LENGTH_LONG).show();
            textView.setText("lelelele");
            break;
    }
}

• 在开发的时候，都是采用String.xml来操作字符串

• 在xml文件中，使用

  android:text="@string/xiao";

• 在java代码中使用

  textView.setText(R.string.xiao)

EditText

@Override
public void onCick(View view){
    switch(view.getId()){
        case R.id.button():
            Log.d("xiaojianbang","onClck");
            Toast.makeText(MainActivity.this,"xiaojianbang",Toast.LENGTH_LONG).show();
            textView.setText("lele");
            String username = editText.getText().toString().trim();
            if(TextUtile.isEmpty(username)){
                Log.d("xiaojiambang","username is null");
            }else{
                Log.d("xiaojianbang",username);
            }
            break;
    }

}