java - 如何去除不同 Activity 中的重复代码？

Question

我的学习中有一些任务。我必须根据选择的单选按钮明确开始 Activity 。例如，我们有两个 Activity 供选择和主要 Activity 。我们选择一个单选按钮并运行 Activity 。但这个小 Activity 都是一样的。该任务没有说明如何处理相同的 Activity 。我想知道如何避免这种代码重复。不改变任务。

public class DisplayOneActivity extends AppCompatActivity {

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

    TextView textView = findViewById(R.id.textView);
    textView.setText(getIntent().getStringExtra(KEY_TEXT));
    textView.setTextColor(getIntent().getIntExtra(KEY_COLOR, Color.RED));

    if (getIntent().getBooleanExtra(KEY_RANDOM_ALIGN, false)){
        Random rnd = new Random(System.currentTimeMillis());
        textView.setTextAlignment(TEXT_ALIGN[rnd.nextInt(TEXT_ALIGN.length)]);
    }

}
}

public class DisplayTwoActivity extends AppCompatActivity {

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

    TextView textView = findViewById(R.id.textView);
    textView.setText(getIntent().getStringExtra(KEY_TEXT));
    textView.setTextColor(getIntent().getIntExtra(KEY_COLOR, Color.RED));

    if (getIntent().getBooleanExtra(KEY_RANDOM_ALIGN, false)){
        Random rnd = new Random(System.currentTimeMillis());
        textView.setTextAlignment(TEXT_ALIGN[rnd.nextInt(TEXT_ALIGN.length)]);
    }

}
}

Answer 1

您可以使用相同的代码创建 BaseActivity，并使用 BaseActivity 扩展 DisplayOneActivity 和 DisplayTwoActivity。

public class BaseDisplayActivity extends AppCompatActivity {

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

    TextView textView = findViewById(R.id.textView);
    textView.setText(getIntent().getStringExtra(KEY_TEXT));
    textView.setTextColor(getIntent().getIntExtra(KEY_COLOR, Color.RED));

    if (getIntent().getBooleanExtra(KEY_RANDOM_ALIGN, false)){
        Random rnd = new Random(System.currentTimeMillis());
        textView.setTextAlignment(TEXT_ALIGN[rnd.nextInt(TEXT_ALIGN.length)]);
    }
}

然后扩展另外两项 Activity 。

public class DisplayOneActivity extends BaseDisplayActivity {

@Override
protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
}
}


public class DisplayTwoActivity extends BaseDisplayActivity {

@Override
protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
}
}