'R' 的目的是什么？

Question

在我的整个项目中，我添加了按钮或可点击的图像按钮。但是我不知道为什么我在 .id.example 之前使用 'R'。我在网上查询过，但没有什么能给我一个明确的答案。谁能解释一下？

private Button DisplayRoutineButton;
private Button ClearRoutineButton;

private static int ImageID = 0;

ImageView activityslotlocationa, activityslotlocationb, activityslotlocationc, activityslotlocationd, activityslotlocatione, activityslotlocationf;

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

    myDb = new Database(this);

    DisplayRoutineButton = (Button) findViewById(R.id.displayroutinebutton);
    ClearRoutineButton = (Button) findViewById(R.id.clearroutinebutton);

    // Display Routine Button
    DisplayRoutineButton.setOnClickListener(new View.OnClickListener() {
        @Override
        public void onClick(View view) {
            Log.d("BUTTON CLICKED", "Display Schedule");
            Intent i = new Intent(MondayRoutineEdit.this, MondayRoutineDisplay.class);
            Log.d("SUCCESSFUL", "Loading Monday Routine Display");
            startActivity(i);
        }
    });

    // Delete Routine Button
    ClearRoutineButton.setOnClickListener(new View.OnClickListener() {
        @Override
        public void onClick(View view) {
            Log.d("BUTTON CLICKED", "Delete Routine");
            deleteRoutine();
            Log.d("SUCCESSFUL", "Routine Deleted");
        }
    });

    // Audio Feedback
    ImageView artactivity = (ImageView) this.findViewById(R.id.artactivityimage);
    final MediaPlayer artsoundeffect = MediaPlayer.create(this, R.raw.art);
    artactivity.setOnClickListener(new View.OnClickListener() {
        @Override
        public void onClick(View v) {
            artsoundeffect.start();
        }
    });

    ImageView bedtimestoryactivity = (ImageView) this.findViewById(R.id.bedtimestoryactivityimage);
    final MediaPlayer bedtimestorysoundeffect = MediaPlayer.create(this, R.raw.bedtimestory);
    bedtimestoryactivity.setOnClickListener(new View.OnClickListener() {
        @Override
        public void onClick(View v) {
            bedtimestorysoundeffect.start();
        }
    });

Answer 1

R.java 是动态生成的 class，在构建过程中创建以动态识别所有资产（从字符串到 android 小部件再到布局），用于 java classes 在 Android 应用程序中。

查看here了解更多详情。

'R' 的目的是什么？

What is the purpose of 'R'?

android

findviewbyid