java - 无法在 Android Studio 中解析方法 'findViewByID(int)'

Question

我刚刚开始为 android 编码，但我收到了错误:android studio 中“无法解析方法‘findViewByID(int)’”

我似乎无法找出问题所在，尝试设置 contentView，实现 OnClickListener，但这些都没有修复任何问题。

下面是完整的代码，MainActivity 方法是这一切发生的地方:

package aprivate.contract.jdeko.dww_registration;

import android.net.Uri;
import android.support.v7.app.AppCompatActivity;
import android.os.Bundle;
import android.view.View;
import android.widget.Button;
import android.view.View.OnClickListener;

import com.google.android.gms.appindexing.Action;
import com.google.android.gms.appindexing.AppIndex;
import com.google.android.gms.common.api.GoogleApiClient;


public class MainActivity extends AppCompatActivity{
    private GoogleApiClient client;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        Button clickButton = (Button) findViewByID(R.id.Btn);
        clickButton.setOnClickListener( new OnClickListener() {

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

    @Override
    public void onStart() {
        super.onStart();

        // ATTENTION: This was auto-generated to implement the App Indexing API.
        // See https://g.co/AppIndexing/AndroidStudio for more information.
        client.connect();
        Action viewAction = Action.newAction(
                Action.TYPE_VIEW, // TODO: choose an action type.
                "Main Page", // TODO: Define a title for the content shown.
                // TODO: If you have web page content that matches this app activity's content,
                // make sure this auto-generated web page URL is correct.
                // Otherwise, set the URL to null.
                Uri.parse("http://host/path"),
                // TODO: Make sure this auto-generated app URL is correct.
                Uri.parse("android-app://aprivate.contract.jdeko.dww_registration/http/host/path")
        );
        AppIndex.AppIndexApi.start(client, viewAction);
    }

    @Override
    public void onStop() {
        super.onStop();

        // ATTENTION: This was auto-generated to implement the App Indexing API.
        // See https://g.co/AppIndexing/AndroidStudio for more information.
        Action viewAction = Action.newAction(
                Action.TYPE_VIEW, // TODO: choose an action type.
                "Main Page", // TODO: Define a title for the content shown.
                // TODO: If you have web page content that matches this app activity's content,
                // make sure this auto-generated web page URL is correct.
                // Otherwise, set the URL to null.
                Uri.parse("http://host/path"),
                // TODO: Make sure this auto-generated app URL is correct.
                Uri.parse("android-app://aprivate.contract.jdeko.dww_registration/http/host/path")
        );
        AppIndex.AppIndexApi.end(client, viewAction);
        client.disconnect();
    }

}

Answer 1

这只是你打错了。您应该使用“Id”而不是“ID”。

所以你的

Button clickButton = (Button) findViewByID(R.id.Btn);

成为

Button clickButton = (Button) findViewById(R.id.Btn);