Eclipse，按钮单击的新活动

Question

我是初学者，但我想修改一个较旧的项目。 在 Preferences Activity 上，已经有几个按钮，但我想添加一个新按钮，单击该按钮会打开一个新 Activity 并仅显示图像。

为此，我在 Manifest 中声明了这项新活动：

<activity
  android:name=".VisualHelpActivity"
  android:screenOrientation="portrait"
  android:theme="@style/AppTheme" >
</activity>

我在关联的 xml 布局上声明了按钮：

<Button
  android:id="@+id/button_visualhelp"
  android:layout_width="match_parent"
  android:layout_height="wrap_content"
  android:onClick="visual_help"
  android:text="Visual Help" />

我创建了新的 VisualHelp 布局 xml：

<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
  android:layout_width="match_parent"
  android:layout_height="match_parent" >
    <ImageView
      android:id="@+id/visualhelp_image"
      android:layout_width="match_parent"
      android:layout_height="match_parent"
      android:scaleType="fitXY"
      android:src="@drawable/guide" />

声明了它的新 VisualHelpActivity java 文件：

public class VisualHelpActivity extends TranslatableActivity {

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

    @Override
    public boolean onCreateOptionsMenu(Menu menu) {
            // Inflate the menu; this adds items to the action bar if it is present.
            getMenuInflater().inflate(R.menu.visual_help, menu);
            return true;
    }

    @Override
    public boolean onOptionsItemSelected(MenuItem item) {
            // Handle action bar item clicks here. The action bar will
            // automatically handle clicks on the Home/Up button, so long
            // as you specify a parent activity in AndroidManifest.xml.
            int id = item.getItemId();
            if (id == R.id.action_settings) {
                    return true;
            }
            return super.onOptionsItemSelected(item);
    }

    @Override
    protected void refreshLanguage() {
    }
}

...现在我应该在“主”PreferencesActivity 中将它们连接在一起，如下所示：

public class PreferencesActivity extends TranslatableActivity {

    public static String url = "https://www.paypal.com/cgi-bin....";

    ImageView donate;

    @Override
    public boolean onOptionsItemSelected(MenuItem item) {
            switch (item.getItemId()) {
            case android.R.id.home:
                    onBackPressed();
                    return true;
            default:
                    return super.onOptionsItemSelected(item);
            }
    }

    @SuppressLint("NewApi")
    @Override
    protected void onCreate(Bundle savedInstanceState) {
            super.onCreate(savedInstanceState);

            getSupportActionBar().setDisplayHomeAsUpEnabled(true);
            setContentView(R.layout.activity_preferences);

            donate = (ImageView) findViewById(R.id.button_donate);
            donate.setOnClickListener(new OnClickListener() {

                    @Override
                    public void onClick(View v) {
                            donate(v);
                    }
            });

            Spinner s = (Spinner) findViewById(R.id.combo_language);
            Lang[] languages = LanguageUtil.Lang.values();

            s.setAdapter(new ArrayAdapter<Lang>(this,
                            android.R.layout.simple_dropdown_item_1line, languages));
            s.setSelection(getPosition(languages, LanguageUtil.getLanguage()), true);
    }

    private int getPosition(Object[] objs, Object item) {
            for (int i = 0; i < objs.length; i++) {
                    if (objs[i] == item)
                            return i;
            }
            return -1;
    }

    public void update(View v) {
            Maintenance.downloadDB(this, new onFinishListener() {

                    @Override
                    public void onFinish() {
                            LanguageUtil.loadLanguage(PreferencesActivity.this);
                    }
            });
    }

    public void copy(View v) {
            Maintenance.copyDB(this, new onFinishListener() {
                    @Override
                    public void onFinish() {
                            LanguageUtil.loadLanguage(PreferencesActivity.this);
                    }
            });
    }

    public void save(View v) {
            LanguageUtil.saveLanguage(this,
                            (Lang) ((Spinner) findViewById(R.id.combo_language))
                                            .getSelectedItem());
            LanguageUtil.loadLanguage(this);
            setResult(RESULT_OK);
            finish();
    }

    public void donate(View v) {
            Intent i = new Intent(Intent.ACTION_VIEW, Uri.parse(url));
            startActivity(i);
    }

    public void cancel(View v) {
            finish();
    }

    @Override
    protected void refreshLanguage() {
            ((Button) findViewById(R.id.button_update)).setText(LanguageUtil
                            .getDeviceLabel(LanguageUtil.dev_update));
            ((TextView) findViewById(R.id.language_label))
            .setText(LanguageUtil.getDeviceLabel(LanguageUtil.dev_language));
    }

}

根据androidbegin.com，我应该将此代码添加到PreferencesActivity java文件中（上面的代码）：

Button button;
@Override
public void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_visualhelp);
    button = (Button) findViewById(R.id.button_visualhelp);
    button.setOnClickListener(new OnClickListener() {
        public void onClick(View arg0) {
    Intent myIntent = new Intent(PreferencesAtivity.this,
        VisualHelpActivity.class);
        startActivity(myIntent);
        }
    });
}

唯一的问题是，如果我尝试添加这个新的public void，会弹出多个标记错误，如果我尝试在其他地方包含所有以下内容，我的应用程序将无法运行。那么，谁能帮我弄清楚在哪里以及如何包含此代码部分以使其工作？

Answer 1

在你的 PreferencesActivity 类中像这样在 oncreate 方法中添加代码：-

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

getSupportActionBar().setDisplayHomeAsUpEnabled(true);
setContentView(R.layout.activity_preferences);

donate = (ImageView) findViewById(R.id.button_donate);
donate.setOnClickListener(new OnClickListener() {

    @Override
    public void onClick(View v) {
        donate(v);
    }
});


button = (Button) findViewById(R.id.button_visualhelp);
button.setOnClickListener(new OnClickListener() {
    public void onClick(View arg0) {
Intent myIntent = new Intent(PreferencesAtivity.this,
    VisualHelpActivity.class);
    startActivity(myIntent);
    }
});
Spinner s = (Spinner) findViewById(R.id.combo_language);
Lang[] languages = LanguageUtil.Lang.values();

s.setAdapter(new ArrayAdapter<Lang>(this,
        android.R.layout.simple_dropdown_item_1line, languages));
s.setSelection(getPosition(languages, LanguageUtil.getLanguage()), true);
}