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好吧，我是 Android 编码的新手，我正在开发一个应用程序来教如何种植一些植物/花卉。我正在使用 SQLite 数据库来存储数据，但是我通过游标调用类中的信息，除此之外我不知道该怎么做，所以我的应用程序真的很慢，我猜是游标错误，但我无法解决这个问题。抱歉我的英语不好，我来自巴西：D。

package com.lmenegalli.homeplanting;

import android.content.Intent;
import android.database.Cursor;
import android.os.Bundle;

import android.util.Log;
import android.view.MenuItem;
import android.view.View;
import android.widget.*;

import androidx.appcompat.app.ActionBar;
import androidx.appcompat.app.AppCompatActivity;

import java.util.ArrayList;
import java.util.Collections;
import java.util.Comparator;

public class FlowersSelectedActivity extends AppCompatActivity {

    ListView listViewSelected;

    int listCounter=0;
    String nomeFlor;
    String categoria;
    ArrayList<String> listItem;

    DataBase dab = new DataBase(this);


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

       final Cursor cursor = dab.alldata();

       //String categoriaFlor = cursor.getString(7);

        listViewSelected=(ListView)findViewById(R.id.array_full);

        final ArrayList<String> arrayListSelected = new ArrayList<>();



        Bundle b = getIntent().getExtras();

        if (b != null) {
                categoria = b.getString("categoria");





            final String aux = categoria;
        }

//        Log.d("Teste categoria", categoria);

        //arrayListSelected.add("teste");




    //=======================================================================
            //Teste do CRUD





        /*Flores flores = new Flores();
        flores.setId(3);
        dab.deleteFlor(flores);*/
        Toast.makeText(FlowersSelectedActivity.this, "Count: "+cursor.getCount(), Toast.LENGTH_SHORT).show();
        if(cursor.getCount()==0){
            Toast.makeText(getApplicationContext(),"NO DATA", Toast.LENGTH_LONG).show();
        } else{
            while(cursor.moveToNext()){
                if(cursor.getString(7).equals(categoria)) {
                    nomeFlor = cursor.getString(1);
                    arrayListSelected.add(nomeFlor);

                }
            }
        }

        ArrayAdapter arrayAdapterSelected = new ArrayAdapter(this,android.R.layout.simple_list_item_1,arrayListSelected);

        listViewSelected.setAdapter(arrayAdapterSelected);

        listViewSelected.setOnItemClickListener(new AdapterView.OnItemClickListener() {
            @Override
            public void onItemClick(AdapterView<?> adapterView, View view, int i, long l) {
                Intent intentSelected = new Intent(FlowersSelectedActivity.this, ImageCard.class);

 String nomeList =(String) adapterView.getItemAtPosition(i);
//I did this because my data was sorted in database, but in ListView not, so when I clicked in something that was sorted, it always get the information of the first item of the list.
                //Log.d("Nome",nomeList);
                    switch (i) {
                        default:

                            cursor.moveToPosition(i);
                            while(!nomeList.equals(cursor.getString(1))) {
                                cursor.moveToNext();
// I guess the problem is here, but I don't know what is wrong.
                            }
                            if(nomeList.equals(cursor.getString(1))){
                                String nome = cursor.getString(1);
                                String descricao = cursor.getString(2);
                                String nomeCientifico = cursor.getString(3);
                                String imagem = cursor.getString(4);
                                String comoPlantar = cursor.getString(5);
                                String imagemPlantio = cursor.getString(6);


                                intentSelected.putExtra("nome", nome);
                                intentSelected.putExtra("descricao", descricao);
                                intentSelected.putExtra("nomeCientifico", nomeCientifico);
                                intentSelected.putExtra("imagem", imagem);
                                intentSelected.putExtra("comoPlantar", comoPlantar);
                                intentSelected.putExtra("imagemPlantio", imagemPlantio);
                                intentSelected.putExtra("categoria", categoria);
                                cursor.close();
                            }
                            break;
                    }
                startActivityForResult(intentSelected, 1);
                }

        });
       // Toast.makeText(FlowersSelectedActivity.this, "Salvo com Sucesso", Toast.LENGTH_LONG).show();


    //========================================================================
        ActionBar actionBar = getSupportActionBar();
        actionBar.setDisplayShowHomeEnabled(true);
        actionBar.setDisplayHomeAsUpEnabled(true);
        actionBar.setTitle(categoria);
    }

    public void voltar(View view){
            Intent intentVoltar = new Intent(this, MainActivity.class);
        getApplicationContext().startActivity(intentVoltar);
    }

    @Override
    public boolean onOptionsItemSelected(MenuItem item){
        int id = item.getItemId();

        if(id == R.id.home){
            this.finish();
        }
        return super.onOptionsItemSelected(item);
    }

    @Override
    protected void onActivityResult(int requestCode, int resultCode, Intent data) {

        if (requestCode == 1) {
            if(resultCode == ImageCard.RESULT_OK){
                if(data.getStringExtra("categoriaa") == categoria){
                    categoria = data.getStringExtra("categoria");
                }
            }
            if (resultCode == ImageCard.RESULT_CANCELED) {
                //Write your code if there's no result
            }
        }
    }

}

编辑：根据要求在下面的 Logcat。

2019-11-04 23:50:33.867 11400-11400/com.lmenegalli.homeplanting I/zygote:     at void android.os.Handler.dispatchMessage(android.os.Message) (Handler.java:106)
2019-11-04 23:50:33.867 11400-11400/com.lmenegalli.homeplanting I/zygote:     at void android.os.Looper.loop() (Looper.java:164)
2019-11-04 23:50:33.867 11400-11400/com.lmenegalli.homeplanting I/zygote:     at void android.app.ActivityThread.main(java.lang.String[]) (ActivityThread.java:6647)
2019-11-04 23:50:33.867 11400-11400/com.lmenegalli.homeplanting I/zygote:     at java.lang.Object java.lang.reflect.Method.invoke(java.lang.Object, java.lang.Object[]) (Method.java:-2)
2019-11-04 23:50:33.867 11400-11400/com.lmenegalli.homeplanting I/zygote:     at void com.android.internal.os.RuntimeInit$MethodAndArgsCaller.run() (RuntimeInit.java:438)
2019-11-04 23:50:33.867 11400-11400/com.lmenegalli.homeplanting I/zygote:     at void com.android.internal.os.ZygoteInit.main(java.lang.String[]) (ZygoteInit.java:811)
2019-11-04 23:50:34.722 11400-11405/com.lmenegalli.homeplanting I/zygote: Do partial code cache collection, code=5KB, data=29KB
2019-11-04 23:50:34.724 11400-11405/com.lmenegalli.homeplanting I/zygote: After code cache collection, code=5KB, data=29KB
2019-11-04 23:50:34.724 11400-11405/com.lmenegalli.homeplanting I/zygote: Increasing code cache capacity to 128KB
2019-11-04 23:50:34.814 11400-11441/com.lmenegalli.homeplanting D/OpenGLRenderer: HWUI GL Pipeline
2019-11-04 23:50:35.032 11400-11441/com.lmenegalli.homeplanting I/Adreno: QUALCOMM build                   : bca571b, I47556f00c5
    Build Date                       : 04/30/18
    OpenGL ES Shader Compiler Version: EV031.22.00.01
    Local Branch                     : 
    Remote Branch                    : quic/LA.BR.1.3.7_rb1.11
    Remote Branch                    : NONE
    Reconstruct Branch               : NOTHING
2019-11-04 23:50:35.150 11400-11441/com.lmenegalli.homeplanting I/Adreno: PFP: 0x004ff087, ME: 0x004ff065
2019-11-04 23:50:35.164 11400-11441/com.lmenegalli.homeplanting I/zygote: android::hardware::configstore::V1_0::ISurfaceFlingerConfigs::hasWideColorDisplay retrieved: 0
2019-11-04 23:50:35.165 11400-11441/com.lmenegalli.homeplanting I/OpenGLRenderer: Initialized EGL, version 1.4
2019-11-04 23:50:35.165 11400-11441/com.lmenegalli.homeplanting D/OpenGLRenderer: Swap behavior 2
2019-11-04 23:50:35.409 11400-11441/com.lmenegalli.homeplanting D/vndksupport: Loading /vendor/lib/hw/android.hardware.graphics.mapper@2.0-impl.so from current namespace instead of sphal namespace.
2019-11-04 23:50:40.714 11400-11405/com.lmenegalli.homeplanting I/zygote: Do partial code cache collection, code=33KB, data=54KB
2019-11-04 23:50:40.716 11400-11405/com.lmenegalli.homeplanting I/zygote: After code cache collection, code=33KB, data=54KB
2019-11-04 23:50:40.716 11400-11405/com.lmenegalli.homeplanting I/zygote: Increasing code cache capacity to 256KB
2019-11-04 23:50:40.903 11400-11400/com.lmenegalli.homeplanting D/Teste drawable: mipmap/babosa_circle
2019-11-04 23:50:40.903 11400-11400/com.lmenegalli.homeplanting D/Teste drawable 2: mipmap/comoplantarbabosa
2019-11-04 23:50:41.586 11400-11405/com.lmenegalli.homeplanting I/zygote: Do full code cache collection, code=123KB, data=98KB
2019-11-04 23:50:41.587 11400-11405/com.lmenegalli.homeplanting I/zygote: After code cache collection, code=112KB, data=62KB
2019-11-04 23:50:42.412 11400-11400/com.lmenegalli.homeplanting I/Choreographer: Skipped 73 frames!  The application may be doing too much work on its main thread.
2019-11-04 23:50:42.460 11400-11405/com.lmenegalli.homeplanting I/zygote: Do partial code cache collection, code=121KB, data=74KB
2019-11-04 23:50:42.466 11400-11405/com.lmenegalli.homeplanting I/zygote: After code cache collection, code=121KB, data=74KB
2019-11-04 23:50:42.466 11400-11405/com.lmenegalli.homeplanting I/zygote: Increasing code cache capacity to 512KB
2019-11-04 23:50:52.672 11400-11441/com.lmenegalli.homeplanting D/OpenGLRenderer: endAllActiveAnimators on 0x86c71480 (RippleDrawable) with handle 0x884de8b0
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3 回答 3

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I/Choreographer: Skipped 73 frames!  The application may be doing too much work on its main thread.

上面的消息基本上是在 Android 的 MainThread/UI 线程工作超载时出现的。原因可能是由于复杂的非 UI 工作、繁重的 Animation 等。

要检查是哪个部分导致的，您可以在运行应用程序时检查 CPU 活动。检查这个强大的官方链接

官方视频教程Android Performance

有帮助就投票

谢谢。快乐编码。

于 2019-11-05T02:23:27.160 回答
0

问题从这一行开始：

final Cursor cursor = dab.alldata();

您直接从 MainThread 访问数据库。在 android 中 MainThread 应该只用于布局更改和 android 框架的东西。您总是需要访问数据库或网络服务器之类的东西，您需要在不同的线程中而不是在 MainThread 中进行访问。您可以开始检查 android 中的 AssyncTasks，您将看到解决方案是在不同的线程中访问这些类型的数据。

我希望它有帮助！

于 2019-11-05T04:45:40.187 回答
0

android 应用程序适用于 Android OS 主线程。当您在主线程上进行大量处理时，会出现此警告。主要是因为从数据库加载数据。所以在你的情况下

    final Cursor cursor = dab.alldata();

if(cursor.getCount()==0){
            Toast.makeText(getApplicationContext(),"NO DATA", Toast.LENGTH_LONG).show();
        } else{
            while(cursor.moveToNext()){
                if(cursor.getString(7).equals(categoria)) {
                    nomeFlor = cursor.getString(1);
                    arrayListSelected.add(nomeFlor);

                }
            }
        }

上面的代码段或您从数据库中获取数据或存储在其中的其他任何地方，都应该在AsyncTask. 我希望它能解决你的问题。

AsyncTask将在后台进行处理并在主线程中发送结果，这样你就可以对数据做任何你想做的事情。

PS 不要尝试从AsyncTask doInBackground方法更新 UI/Adaptor。

于 2019-11-05T05:37:51.167 回答